nGen HORRENDOUS glopping

I printed a lot of PLA and was extremely happy with it. Then I switched to eSun PETG, which turned out to be extremely fussy. But after many days of controlled experiments, I got things tweaked to the point that PETG almost always printed well, even in a hot shop that PLA could not tolerate due to heat creep. But I needed a metallic silver, so I bought that with nGen. This morning I used the Lulzbot 5 Fine profile with fill raised from 20% to 50% for strength, and it was disaster. The first layer went down perfectly, sticking well and with neglibible strining (a major PETG fault). A few subsequent layers built up fine, with no real stringing or boogers. So I went away and came back an hour later. Yikes! The filament was one huge blob stuck to the extruder head, moving back and forth with it as more and more filament extruded. Does anyone have a thought on why this happened?

Addendum… I just noticed that Lulzbot says to use a bed temperature of 85, which is what I did, while the manufacturer’s site says 60. Maybe that’s an issue?

85 bed is the upper limit. Glas transition temperature is 75 to 85°c, so I will start with 80.
I would check esteps and filament diameter settings first, maybe ngen behaves different.

I will get my first ngen today, I’m excited if it’s worth 2x the price of esun pla :sunglasses:

I just tried again, this time with Gold (the only other nGen filament I have here right now). I watched it closely and saw this happen in slow motion.

The first layer went down excellently, with perfect adhesion (still with an 85 degree bed, though I’ll try dropping that) and negligible stringing. But the second layer did not stick AT ALL to the first (bottom) layer. It just kept right on moving with the print head, back and forth as more and more filament built up on the head. Sigh. Any more thoughts, now that I have this additional information?

Hi TinM,

nGen is printing beautifully on my Lulzbot mini. I’m using regular black btw. My bed is set to 85 and and my nozzle to 230. What is your nozzle temperature at?

Per Lulzbot recommendation, head at 230 and bed at 85. Their ‘Fine’ .ini file unchanged except for raising infill percent from 20 (which is too weak for my stuff) to 50. PLA prints beautifully, and PETG quite well.

The weird thing is that the first layer goes down beautifully, with no boogers and only the tiniest hint of stringing. The problem comes with the next layer sticking to the first layer. It doesn’t. It just rides along with the moving head, a steadily growing blob skating back and forth across the first layer.

Maybe it’s the ‘metalic gold’ that’s the problem.


Try thicker layer heights.

Could try to increase extrusion temps by 1-2C to help bonding of layers. Decreasing cooling may help also. Basically sounds like the extruded filament is cooling too fast to stick to the previous layer.